Mf 690, blowing onring on hydraulic coupling.

[TexelBen]

Had the tractor about a year now, recon I've replaced this o ring on the rear valve block 10 times now, it can be good more for a few days of work then blow again, any ideas?
I found an o ring that seems to fit the one that came off the first time and keep replacing it.

 

[sawdust]

Fit 90 shore O ring see if that makes a difference

 

[MF-ANDY]

Replace all those fittings with screw on 3/4 jic fittings. Changed no end in my time